Engine starter gearing



Feb. 16, 19 43. P, KEARNEY 2,311,297

ENGINE STARTER GEARING Filed Odt. 11, 1941 F r m if! I; i 111/ 43 49 2M INVENTOR.

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Patented Feb. 16, 1943 UNITED STATES PATENT ()FFICE z,311,297 ENGINE STARTER QEARING Daniel P. Kearney, Birmingham, Mich, assi'gno'r to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 11, 1941, Serial No. 414,559

Claims.

The present invention relates to engine starter gearing and more particularly to a starter drive of the automatically engaging and disengaging type.

In starting systems for internal combustion engines having a small number of cylinders the cranking speed fluctuates considerably as the engine goes over its compression points. When a starter drive of the automatic type is employed,

engine gear irrespective of minor accelerationssuch as may be caused by weak explosions of the engine.

It is another object to provide such a device which is simple and economical in construction and reliable in operation.

It is a further object to provide such a device which is arranged to permit the drive pinion to run ahead of the drive to a limited extent before initiating the demeshing movement of the pinion.

It is another object to provide such a device which provides a positive driving connection to the pinion.

It is another object to provide such a device which is independent of the absolute speed of rotation of the parts.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. l is a side elevation partly in section of a starter drive embodying a preferred form of the invention;

Fig. 2 is a similar view of a portion of the drive showing the parts in driving relationj and Fig. 3 is a view similar to Fig. 2 showing the parts as they are returning to idle position.

In the drawing there is illustrated a power shaft l on which a sleeve 2 is fixed as by means of a cross pin 3. Sleeve 2 is provided with a drive head 4 at one end having a non-circular cross section, and a driving anchor plate 5 having an opening conforming to the periphery of the drive head is slidably but nonrotatably mounted thereon. A screw shaft 6 is slidably journalled on the sleeve 2, being retained thereon by an abutment in the form of a stop nut I fixed on the end of the sleeve. Screw shaft 6 is provided with a driven head 8 of non-circular contour, and a driven anchor plate 9 having an opening conforming therewith is slidably but nonrotatably mounted thereon. A coiled drive spring i I is mounted between the anchor plates 5 and 9 and is provided with terminal lugs I2 and I3 engaging in slots in said anchor plates so as to provide a yielding driving connection therebetween. The driving anchor plate 5 is retained on the driving head 4 by means of a lock ring l4 and the driven anchor plate 9 is retained on the driven head 8 by means of a shoulder l5 formed thereon.

A pinion i6 is slidably journalled on the power shaft l for movement into and out of engagement with a member such as a gear I! of an engine to be started. A nut I8 is mounted on the screw shaft 6, and a barrel member I9 is rigidly connected thereto as by means of radial lugs 2| on the nut seated in slots 22 in one end of the barrel and retained therein by means of a lock ring 23. The other end of the barrel is provided with an inturned flange 24 which is journalled on an extended hub 25 of the pinion I6 and is retained thereon by suitable means such as a lock ring zfi'whereby' the barrel has a swiveled connection with the pinion.

The flange 24 of the barrel has a driving lug 21 extending axially therefrom, and the pinion I6 is provided with a flange 28 on which a driven abutment lug 29 is fixed in position to be engaged by the driving lug 21. Yielding means normally holding the driving and driven lugs in engagement is provided in the form of a torsion spring 3| attached at its ends to the flanges 24 and 28 as indicated at 32 and 33 respectively. The pinion is thus normally maintained positively connected to the barrel for transmission of cranking torque, but may run ahead of the barrel when the .engine starts, to the extent of nearly a complete revolution.

In the operation of the device, rotation of the power shaft l is yieldably transmitted to the screw shaft 6 through the spring H, causing traversal of the nut 18, barrel l9 and pinion I6 until the pinion is meshed with the engine gear ll at which time the nut i 8 engages the stop nut i and rotation is transmitted to the pinion to crank the engine. The cranking load causes the screw shaft 6 to move backward, compressing the spring ll until the travel of the screw shaft is stopped by abutment of the driven head 8 against the driving head 4. Thereafter the cranking torque is transmitted yieldingly by virtue of the torsional elasticity of the drive spring.

. with the engine gear until a sufficiently strong explosion or series of explosions occurs to cause the pinion to overrun the barrel until the pinion lug 29 strikes the rear side of the driving lug 21 on the barrel and thereby accelerates the barrel to a higher speed than that of the power shaft. When this occurs, the engine has become reliably self-operative, and the pinion and its associated parts are returned to their idle positions by the overrunning action of the nut l8 on the screw shaft, 6, as shown in Fig. 3 where they are yieldably retained by suitable means such as an anti-drift spring 34.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and that changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starterdrive a power shaft, a sleeve fixed thereon, a screw shaft yieldably connected to rotate with the sleeve, a nut on the screw shaft, a pinion slidably journalled on the power shaft for movement into and out of engagement with a member of-an engine to be started, a stop for the nut, and means connecting the pinion for rotation and longitudinal movement with the nut including a barrel member fixed to the nut, a lost motion connection between the barrel and pinion, and yielding means normally taking up said lost motion in the driving direction.

2. In an engine starter drive a power shaft, a sleeve fixed thereon, a screw shaft yieldably connected to rotate with the sleeve, a nut on the screw shaft, a pinion slidably journalled on the screw shaft, a pinion slidably journalled on 'the power shaft having a swiveled connection I with the nut, a driving abutment fixedly connected to the nut, a driven abutment fixedly connectedto the pinion, and means including a coiled spring normally holding the abutments in driving engagement but yieldable to permit the pinion to overrun the nut.

4. In an engine starter drive a power shaft. a pinion journalled thereon for longitudinal movement into and out of engagement with a member of an engine to be started, a yielding driving connection from the power shaft to the pinion including a barrel member having a swiveled connection to the nut, and having a driving lug, said nut having an abutment adapted to be engaged and rotated by the driving lug, and a spring normally holding the abutment in contact with the driving lug.

1 5. In an engine starter' drive a power shaft, a pinion journalled thereon for longitudinal movement into and out of engagement with a member of an engine to be started, a yielding driving connection from the power shaft to the pinion including a barrel member having a swiveled connection to the nut, and having a driving lug, said nut having an abutment adapted to be engaged and rotated by the driving lug, and a coiled spring anchored at its ends to the barrel and pinion and exerting sufficient torsion on the pinion to prevent the abutment from drifting away from the driving lug when the parts are in idle position, but permitting the pinion to overrun the barrel when the engine starts.

DANIEL P. KEARNEY. 

